web.xml

Other

Automatic Deployment - Use cases

Table of Contents

Introduction

This page defines the expected behaviour of the automatic deployer in many
typical use cases. This is a complex area of Tomcat's functionality.
While any difference between this document and Tomcat's behaviour is a
bug, the fix may be to change this document, Tomcat's behaviour or
both.

Key

Term

Description

XML

An XML configuration file located in the Host's
configBase. It must contain a single <Context> element
and may contain optional nested elements. It does not define an
explicit docBase attribute. It represents a single web
application. It is often referred to as a context.xml file.

XML+EW

An XML configuration file located in the Host's
configBase. It must contain a single <Context> element
and may contain optional nested elements. It includes an explicit
docBase attribute that points to an external WAR. It
represents a single web application. It is often referred to as a
context.xml file.

XML+ED

An XML configuration file located in the Host's
configBase. It must contain a single <Context> element
and may contain optional nested elements. It includes an explicit
docBase attribute that points to an external directory. It
represents a single web application. It is often referred to as a
context.xml file.

WAR

A WAR file located in the Host's appBase. The WAR does
not include an embedded context.xml file.

WAR+XML

A WAR file located in the Host's appBase. The WAR does
include an embedded context.xml file.

DIR

A directory located in the Host's appBase. The directory
does not include an embedded context.xml file.

DIR+XML

A directory located in the Host's appBase. The directory
does include an embedded context.xml file.

redeploy

The Context object that represents the web application is destroyed
and a new Context object is created. If present and permitted by the
configuration, this new Context object is created by parsing the
context.xml file. The web.xml file is parsed during the application
start process. Any sessions stored in the standard Manager in the
default configuration will not be persisted. Any requests to the web
application during the redeploy will be handled as if the web
application is not deployed.

reload

The Context object that represents the web application is stopped and
then started. The web.xml file is parsed during the application start
process. Any sessions stored in the standard Manager in the default
configuration will not be persisted. Any requests to the web
application during the reload will be held until the reload completes
at which point they will continue using the reloaded web application.

New files

This section describes Tomcat's behaviour when the automatic
deployment process discovers a new web application.

Starting artifact(s)

Configuration Settings

Result

deployXML

copyXML

unpackWARs

XML

WAR

DIR

Notes

XML

either

either

either

Y

N

N

1, 2, 3

XML+EW

either

either

false

Y

N

N

1

XML+EW

either

either

true

Y

N

Y

1

XML+ED

either

either

either

Y

N

N

1, 2

WAR+XML

false

either

false

N

Y

N

4

WAR+XML

false

either

true

N

Y

Y

4

WAR+XML

true

false

false

N

Y

N

WAR+XML

true

false

true

N

Y

Y

WAR+XML

true

true

false

Y

Y

N

WAR+XML

true

true

true

Y

Y

Y

WAR

either

either

false

N

Y

N

WAR

either

either

true

N

Y

Y

DIR+XML

false

either

either

N

N

Y

4

DIR+XML

true

false

either

N

N

Y

DIR+XML

true

true

either

Y

N

Y

DIR

false

either

either

N

N

Y

Deleted files

This section describes Tomcat's behaviour when the automatic
deployment process detects that a web application file has been deleted.

When a file is deleted or modified any redeploy resources that are listed
after the modified/deleted resource are themselves deleted (and possibly
re-created). The order of redeploy resources is:

WAR

DIR

XML

global resources

There are some exceptions to the deletion rule above:

global resources are never deleted

external resources are never deleted

if the WAR or DIR has been modified then the XML file is only deleted if
copyXML is true and deployXML is
true

In the following table:

'-' means "unchanged from not present". i.e. the artifact wasn't present
before the change and isn't present after it either. '-' rather than 'N'
is used to focus attention on what changes.

'R' means that the directory is re-created by expanding the WAR file.
This will only happen if unpackWARs is true.

'XW' means that the if the WAR contains a META-INF/context.xml file it
will be extracted and placed in the Host's configBase.
This only happens if copyXML is true and
deployXML is true.

'XD' means that the if the directory contains a META-INF/context.xml
file it will be copied to the Host's configBase. This only
happens if copyXML is true and deployXML
is true.

Artifacts present

Artifact removed

Artifacts remaining

XML

WAR

DIR

XML

WAR

DIR

Notes

N

N

Y

DIR

-

-

N

N

Y

N

WAR

-

N

-

N

Y

Y

DIR

-

Y

R

N

Y

Y

WAR

-

N

N

Y

N

N

XML

N

-

-

Y

N

Y

DIR

N

-

N

5

Y

N

Y

XML

XD

-

Y

Y

Y

N

WAR

N

N

-

5

Y

Y

N

XML

XW

Y

-

Y

Y

Y

DIR

XW

Y

R

Y

Y

Y

WAR

N

N

N

Y

Y

Y

XML

XW

Y

Y

Y

Y (external)

N

WAR

Y

N

-

3

Y

Y (external)

N

XML

N

Y (external)

-

6

Y

N

Y (external)

DIR

Y

-

N

3

Y

N

Y (external)

XML

N

-

Y (external)

6

Y

Y (external)

Y

DIR

Y

Y (external)

R

Y

Y (external)

Y

WAR

Y

N

N

3

Y

Y (external)

Y

XML

N

Y (external)

N

6

Modified files

This section describes Tomcat's behaviour when the automatic
deployment process detects that a web application file has been modified.

In the following table:

'-' means "unchanged from not present". i.e. the artifact wasn't present
before the change and isn't present after it either. '-' rather than 'N'
is used to focus attention on what changes.

'M' means that the artifact has been modified.

'R' means that the directory is deleted and re-created by expanding the
WAR file. This will only happen if unpackWARs is
true.

Artifacts present

Artifact modified

Artifacts remaining

XML

WAR

DIR

XML

WAR

DIR

Action

N

N

Y

DIR

-

-

M

None

N

Y

N

WAR

-

M

-

Redeploy

N

Y

Y

DIR

-

Y

M

None

N

Y

Y

WAR

-

M

R

Redeploy

Y

N

N

XML

M

-

-

Redeploy

Y

N

Y

DIR

Y

-

M

None

Y

N

Y

XML

M

-

Y

Redeploy

Y

Y

N

WAR

Y

M

-

Reload

Y

Y

N

XML

M

Y

-

Redeploy

Y

Y

Y

DIR

Y

Y

M

None

Y

Y

Y

WAR

Y

M

R

Reload

Y

Y

Y

XML

M

Y

Y

Redeploy

Y

Y(external)

N

WAR

Y

M(external)

-

Reload

Y

Y(external)

N

XML

M

Y(external)

-

Redeploy

Y

N

Y(external)

DIR

Y

-

M(external)

None

Y

N

Y(external)

XML

M

-

Y(external)

Redeploy

Y

Y(external)

Y

DIR

Y

Y(external)

M

None

Y

Y(external)

Y

WAR

Y

M(external)

R

Reload

Y

Y(external)

Y

XML

M

Y(external)

Y

Redeploy

Added files

This is treated as if the added file has been modified with the following
additional actions:

If a WAR is added, any DIR is removed and may be recreated depending on
unpackWARs.

If an XML file is added that refers to an external docBase any
WAR or DIR in the appBase will be removed. The DIR may be recreated if
the external resource is a WAR and unpackWARs is true.

If a DIR is added when a WAR already exists and unpackWARs is
false, the DIR will be ignored but a warning will be
logged when the DIR is first detected. If the WAR is removed, the DIR
will be left and may be deployed via automatic deployment.

If a WAR is added to the appBase when an external WAR already
exists, the WAR in the appBase will be ignored but a warning
will be logged when the WAR in the appBase is first detected.
If the external WAR is removed, the WAR in the appBase will be
left and may be deployed via automatic deployment.

If an XML file is added to the META-INF directory of an application
deployed from that DIR, the application will always be redeployed. The
result will be the same as for a new deployment.

Notes

deployXML and copyXML are ignored since an XML file
was discovered in the configBase.

unpackWARs is ignored since there is no WAR file.

The context will fail to start because there is no content in the
expected docBase.

The web application fails to deploy because it contains an embedded
META-INF/context.xml, deployXML is false and an
XML has not been provided in the configBase.

The XML file is only deleted if copyXML is true
and deployXML is true.

Although the external resource is still present, the web application is
fully undeployed as Tomcat has no knowledge of the external resource.